There is very limited information about the epidemiology of Type 2 diabetes mellitus in youth, though it is believed that the prevalence is increasing rapidly. Risk factors similar to those in adults with Type 2 are thought to be important, (e.g., obesity, insulin resistance, diet, physical activity, positive family history), however, there are no reliable epidemiological studies of these risk factors in youth with type 2 diabetes using appropriate controls. In addition, risk factors such as low birth weight lack of breast-feeding, maternal diabetes during pregnancy and family dysfunction and depressive symptoms have received little epidemiological study in populations other than American Indians. This application addresses the lack of such studies. The Defining Diabetes in Youth (DDY) project will focus on type 2 diabetes in youth aged 10-19, drawing upon the CDC funded SEARCH diabetes registry project in Colorado and South Carolina. The SEARCH project will ascertain all cases of diabetes in youth, collect immunologic, clinical, and metabolic information, and classify cases as Type 1 or 2 diabetes. DDY will only have to recruit appropriate controls aged 10-19 from three ethnic backgrounds including African Americans (AA), Hispanics (H), and non-Hispanic whites (NHW) to test specific etiologic hypotheses in the cases classified by SEARCH as Type 2 diabetes. It will also explore cardiovascular risk factor differences in youth with Type 2 diabetes and controls, and will evaluate insulin resistance and secretion differences among controls by level of obesity and other factors. The primary design is a case-control study, through which risk factors for diabetes, selected complications and CVD risk factors will be evaluated. The current application is an approved SEARCH ancillary study. Collaborating investigators bring expertise in multiple areas relevant to diabetes in youth, and experience in large epidemiological studies of diabetes (both type 1 and 2) in minority populations. Given the low prevalence of Type 2 in Youth, DDY is an efficient design, since case ascertainment and typing will be conducted by SEARCH, and only control recruitment, addition of new measures, and analysis are requested. The biostatistical analysis, data management and central laboratory will be the same as used in SEARCH.